Nadia Thorpe, with Little Arches Boutique Hotel in Barbados, said in a phone interview that the restaurant would be closed for safety and guests would be given sandwiches and snacks instead. However, she noted the storm had not yet generated much rain or wind.

"People are on the beach," she said. "It looks like a normal day so far."

Tropical storm warnings were issued for St. Lucia, Dominica, Martinique, the U.S. and British Virgin Islands, and Puerto Rico. A tropical storm watch is in effect for the eastern Dominican Republic.

"It looks like we're just beginning to see the start of it," Junius St. Hill, acting lead fireman, said by phone. "Today's a holiday, so most people would be indoors anyway."

Antigua-based regional airline LIAT also canceled several flights in Dominica and St. Lucia.

Bertha is expected to generate up to 3 inches (8 centimeters) of rain across the eastern and northern Caribbean, with isolated amounts of up to 6 inches (15 centimeters) in certain areas.

Officials in Puerto Rico are welcoming the rainfall amid a moderate drought that has hit the island's southern region and a small portion in the northeast. More than half of the U.S. territory also is experiencing abnormally dry conditions, with the government reporting $20 million in crop losses.

"Whether it falls where it needs to fall, that's still to be seen," said Jose Antonio Estrada, National Weather Service meteorologist.

He said the storm is moving quickly and that its effects would be felt all day Saturday in Puerto Rico.

It rained less than an inch in June in Puerto Rico, compared with the month's average of more than 4 inches. July saw more rain, but the 3.40 inches (8.64 centimeters) that fell was still down from the average of 4.76 inches (12 centimeters).

If dry conditions persist, hundreds of thousands of people living in and around the capital of San Juan would get water every other day.